The invention relates to discharge apparatus for discharging broken-off fastener parts from fastener installation apparatus. Fasteners in which a part of the fastener is broken off at the completion of installation of the fastener have been known and used for many years. One example is the blind breakstem rivet which is installed by pulling on the stem, part of which stem then breaks off. Of recent years there has been a requirement that fasteners are installed or placed more rapidly, i.e. with as little time as possible between the installation of successive fasteners by the stem installation apparatus. This has led to the development of automatically operated installation system in which fasteners are fed, automatically, in succession to an installation head, which may, for example, be mounted on the end of a robot arm. However, it is also necessary to remove the broken-off parts of the fasteners which result.
Such installation heads are commonly pneumatically operated, and it is convenient to use air-flow to feed new fasteners to the head and also to remove broken-off parts from the head. In order to minimize the number of connections, such as hoses, going to the installation head, it is convenient to provide the air-flow to remove the broken-off fastener parts from the head along a flexible hose by exhausting air from the hose at or near the end of the hose remote from the installation head. It has been proposed to connect the remote end of the hose to a substantially air-tight receptacle for broken-off fastener parts, from which receptacle air is exhausted to provide the air-flow along the flexible hose. However, with increasing fastener installation rates, it becomes necessary to open the receptacle more frequently to empty out the collected parts. Each opening destroys the vacuum in the receptacle and hose and stops the flow of air along the hose, which means that operation of the associated installation apparatus must be stopped until the receptacle has been closed again and re-exhausted by the air-exhaust means. Such delays are unacceptable in a continuously operating fastener installation system, for example used on a moving production line. In addition, it has been found that the level of vacuum applied to the sealed receptacle causes mechanical fatigue problems with the air seals on the door of the receptacle, and also with the body of the receptacle itself. The result is that the size of the receptacle has to be limited, which means that the receptacle has to be opened for emptying even more frequently.